There are a number of utilities commonly provided to domestic and commercial sites. Such utilities can include gas, electricity and water. Metering can be used at each site in order to determine the amount of the utility being consumer by the site. While individual electricity and gas meters are reasonably common for many sites, individual water meters are not as common. The leakage or escape of gas from the supply system or appliances within a site is detectable owing to the smell. Electricity is not a fluid and therefore does not in principle leak or escape.
Much water leakage is not easy to discover or detect as much of the water supply system is buried underground. Some leakage or escape of water is obviously detectable including leaks where the effect of the leak is visible above ground and/or where it affects a customer's supply. These leaks are commonly referred to as ‘Reported’ leaks. Other hidden leaks, commonly referred to as ‘Unreported’ leaks can be detected using acoustic techniques. However, ‘Reported’ and ‘Unreported’ ‘known’ leaks from water supply systems may account for possibly less than half of the water lost from a water supply system. The remainder, commonly referred to as ‘Background’ leakage is not obvious and is not detectable using currently available techniques.
Some of the leakage may simply be leaks from the water supply system which do not give rise to any visible effect or which are too small to be reliably detected by acoustic techniques. Some flow of water that the water utility considers to be leakage using current analytical and measurement techniques, may in fact be due to flows into storage cisterns and tanks which is subsequently used or consumed. Even if a leak could in principle be discovered using an acoustic technique, this may not be practicable or economic in reality owing to the size of the water supply system and the need to carry out an exhaustive search. Also, fresh leaks may occur at any time.
Hence, it would be beneficial to be able more easily to identify likely locations where water is being lost or wasted by methods other than acoustics.